Advanced flexible Li-ion capacitors with both the anode and cathode derived from the fiber precursors confining MOFs

Flexible lithium ion capacitors (FLICs) integrating the advantages of high energy batteries and high power capacitors are promising for wearable electronic devices. However, the imbalance of the two electrodes in kinetics and capacity impedes their practicable application. To address this challenge, in this article, metal-organic frameworks (MOFs) were introduced to the fiber precursors of both anode and cathode materials to improve the electrochemical performance. Free-standing Cu-BTC derived CuS_x/CF-1.5 anode material and ZIF-8 derived Zn-PCF-900 °C cathode material were separately prepared through the facile blow-spinning technique. Benefitting from the uniformly carbon-encapsulated CuS_x nanoparticles, multilevel mesoporous structure of the CuS_x/CF-1.5 anode and the hierarchical pore structure, large BET surface area of the Zn-PCF-900 °C cathode, Li-ion capacitor (LIC) based on these electrodes can effectively alleviate both the kinetic and capacity imbalance and deliver remarkable energy and power densities (106 Wh kg⁻¹ at 243 W kg⁻¹, 10 Wh kg⁻¹ at 90 kW kg⁻¹). In addition, the FLIC pouch cell also demonstrates its chargeable ability under different bending conditions, revealing good application prospects in high-performance flexible electronic devices.